1. Field of the Invention
The invention relates to image capture lens modules and more particularly to high performance wafer-level packaged image capture lens modules.
2. Description of the Related Art
Digital cameras utilizing high-resolution electronic imaging sensors typically require high resolution optical components such as image capture lens modules. The design and manufacturing of camera modules for portable electronic products is extremely challenging. Some pervasive factors include: high production volume, constant price erosion, size limitations and changing performance and functionality requirements.
Image capture lenses on a digital camera module that focus a scene onto an imager can be as few as one lens on a digital camera module, or as many as four in a digital camera module with mega pixel resolution. Usually, the lenses are plastic, due to lower costs. However, higher quality digital cameras sometimes use glass for the first lens because of its superior optical properties.
Japanese Patent Application Laid-Open No. 2008-287006, the entirety of which is hereby incorporated by reference, discloses an imaging lens with aberration correction, a short optical length, a secured back focus, and steady optical performance in a high temperature environment.
FIG. 1 is a schematic view illustrating a configuration of a conventional imaging lens. Referring to FIG. 1, an imaging lens includes a first diaphragm S1, a first junction type compound lens 10, a second diaphragm S1, and a second junction type compound lens 20 all of which are arranged in sequence from an object side to an image side. The first junction type compound lens 10 includes a first lens L1, a second lens L2, and a third lens L3 arranged in sequence from an object side to an image side. The second junction type compound lens 20 includes a fourth lens L4, a fifth lens L5, and a sixth lens L6 arranged in sequence from an object side to an image side. A cover glass 30 is inserted between the second junction type compound lens 20 and an image sensing element 40. Conventionally, the imaging lens is packaged using wafer level packaging technology. There are, however, some problems for the conventional wafer-level packaged image capture lens module, such as exacerbated optical performances, limitations to substrate and lens replication processes and alignment inaccuracies of the optical center of the lens module.
US Pub. No. 2007/0126898, the entirety of which is hereby incorporated by reference, discloses a three-compound lens module which uses wafer to wafer bonding to stack lens elements. Note that, commonly, the conventional art does not describe lens design of wafer level compound lens, mainly because of worsening optical performances when compared with conventional high quality stacked lens modules, such as plastic lens modules or glass lens modules.
For some applications, a small chief ray angle (CRA) of an image detector is designed for superior image performances. Meanwhile, conventional lens designs are not suitable for low module height and small lens scale requirements. Thus, allowing reduction of the height of the image capture lens module when compared to prior art. Note that if the FFL of an image capture lens can be reduced, image blemish effect may easily be eliminated.